By Chris Chaney on behalf of NARM – The National Association of Rooflight Manufacturers
I was interested to read the article ‘There’s still time to go green’ by Celia Copping in Issue 175 of Roofzine. The point was well made that in the current economic climate, price is often considered more important than environmental performance. Whilst the government is making the noises that we are going green and headed for zero carbon the reality is often very different.
The rooflight industry has a major part to play in the green revolution. Our products, if designed and used correctly, save energy when used as part of a coordinated lighting strategy, as well as reducing heating/cooling costs, by making use of natural resources instead of man-made carbon generating alternatives.
However, the suitability, clarity and enforcement of the regulations and standards applying to roof lights disadvantages the responsible companies that produce compliant, tested and certified products over those who simply ‘weld something together on the cheap’ with no testing and no certification. This is because as Celia Copping has previously pointed out: some contractors are often only interested in price. In these cases, the cheapest gets the job regardless of certification and conformity. A good example of this is thermal performance of rooflights. A contractor will often ask for the ‘U’ value of the product and indeed needs this to confirm that his building meets the Building Regulations. However, in the case of glass roof lights, the figure given to him is often the ‘Centre Pane’ U value for the double glazed unit provided by the Glass supplier, which bears no relation to the overall ‘U’ vale for the complete structure including any framework.
A graphic illustration of this is to observe snow on a rooflight. The snow on the frame of a poorly designed unit will melt before the snow on the glass. The thermal performance of the frame is critical to heat loss from the building. A quality manufacturer of rooflights will provide an overall ‘Ud’ value for the entire unit including the frame – not just the glass. To achieve this figure the reputable rooflight manufacturer will have used complex thermal modelling or ‘Hot Box’ testing techniques, which are expensive, to ensure not only the glass but the frame also meets the specification. This results in a product with a higher cost to the contractor but provides improved and compliant long term thermal performance to the client.
By not bothering to design or consider the overall system to meet the required specification, poor quality rooflight manufacturers get away with providing the wrong figure because their products are cheaper. It’s not right, but it happens every day. This approach also represents a significant risk to the main contractor. Replacing roof lights that fail to meet the specification or which do not perform as expected, is an expensive excercise. The cheaper option may ultimately end up being more costly, both in financial terms and to the main contractor’s reputation.
The situation should improve with European Standards and CE marking coming into place for the Construction Industry, but we have a long way to go before we can CE mark in the rooflight industry because there simply aren’t sufficient harmonised European Standards (hEN) or European Technical Assessments (ETA) agreed to CE mark against. There have been examples of companies claiming and issuing a CE mark to gain commercial advantage, where the CE mark is totally invalid being against the wrong standard or with a Declaration of Performance (DoP) unsupported by any recognised testing. Again done on the ‘cheap’.
The Designated Market Surveillance Authority for this situation in Great Britain , England, Scotland and Wales is The Trading Standards Institute. The problems of non-conforming or untested products should be picked up by the Building Control on the project and reported to Trading Standards but in our sector this has been subject to interpretation and is not reliable. If we are to move to a greener environment, if building control or trading standards are not picking up the baton, then the responsibility must lie with the client and the industry itself to police their market sector contractors for conformity to standards. This does require a level of knowledge and understanding of the current regulation and standards. In the case of our industry sector the National Association of Rooflight Manufacturers provide information on their website ( www.narm.org.uk ) to help and take responsibility to verify their members who commit to make sure that ‘All performance claims we make for our products are verifiable and we will provide evidence for inspection on request’. To install a non-conforming product which has been substantiated by incorrect and incomplete data, may be the biggest mistake and a significant contributor to the performance gap between the building design vs actual which is currently under investigation by the Zero Carbon Hub.